High in Peru’s Andes Mountains, at an elevation of 7,710 feet (2,350 meters), Machu Picchu—the site of ancient Incan ruins—lay hidden away, known only to local residents, for centuries. That was, until July 24, 1911, when Yale University professor Hiram Bingham was led to the site by a local. In search of the “lost city of the Incas” (Vilcabamba, or Vilcapampa), Bingham was sure he had found it when he stepped foot into the narrow saddle between Machu Picchu (“Old Peak”) and Huayna Picchu (“New Peak”).

Alas, Machu Picchu turned out not to be the lost city. As Britannica recounts:

[Bingham] cited evidence from his 1912 excavations at Machu Picchu, which were sponsored by Yale University and the National Geographic Society, in his labeling of the site as Vilcabamba; however, that interpretation is no longer widely accepted. (Nevertheless, many sources still follow Bingham’s precedent and erroneously label Machu Picchu as the “lost city of the Incas.”) Evidence later associated Vilcabamba with another ruin, Espíritu Pampa, which was also discovered by Bingham.

Lost city or not, Machu Picchu provides a stunning glimpse into Inca civilization. Yet, even after a century of exploring the site, mysteries remain. According to Britannica:

Machu Picchu’s construction style and other evidence suggest that it was a palace complex of the ruler Pachacuti Inca Yupanqui (reigned c. 1438–71). Several dozen skeletons were excavated there in 1912, and, because most of those were initially identified as female, Bingham suggested that Machu Picchu was a sanctuary for the Virgins of the Sun (the Chosen Women), an elite Inca group. Technology at the turn of the 21st-century, however, identified a significant proportion of males and a great diversity in physical types. Both skeletal and material remains now suggest to scholars that Machu Picchu served as a royal retreat. The reason for the site’s abandonment is also unknown, but lack of water may have been a factor.

In 1983 Machu Picchu became a UNSECO World Heritage site. Today, it serves as a vital tourist attraction for Peru. Of course, getting there isn’t trivial. As Britannica relates:

The ruins are commonly reached in a day trip from Cuzco by first taking a narrow-gauge railway and then ascending nearly 1,640 feet (500 metres) from the Urubamba River valley on a serpentine road. Smaller numbers of visitors arrive by hiking the Inca Trail. The portion of the trail from the “km 88” train stop to Machu Picchu is normally hiked in three to six days. It is composed of several thousand stone-cut steps, numerous high retaining walls, tunnels, and other feats of classical engineering; the route traverses a wide range of elevations between about 8,530 and 13,780 feet (2,600 and 4,200 metres), and it is lined with Inca ruins of various types and sizes. At Machu Picchu there is a hotel with a restaurant, and thermal baths are at the nearby village of Aguas Calientes.